Riveter



Feb. 28, 1928. l,660,720

R. s. osBoRN RIVETER Filed Feb. 13. 1926 Patented Feb. 28, 1928.

uNrraDf'sTATss L BLYHOND S. OSBOBNE, WYOMING, OHIO.

IB-IVETER.

Application filed February 13, 1926. Serial No. 88,159.

My invention relates Ato improvements in compression riveters which act by direct ressure, and is particularly directed to a evice for automatically controlling the '6 'pressure developed within the rveter and against the work.

Ordinarily the rveter operates under the' entire line res'sure, the full pressure being exerted on t e rivetregardless ofthe size of rivet or the type of work which' is being done. By this method there is a' considerable waste of power and time and frequently the work is damaged by excess pressure.

` Especially is this so in field work where a 1| unlform'pressure must be maintained in the line for Operating other pneumatic devices and often this ressure being excessive for ,i the type of wor bein riveted.

It is highly desirale that it be possible to use the same riveter for a large'range in size of rivets and for any weight of work, this necessitating a means for relieving the pressure to the cylinder at a predetermined degree or at ,the time when the rivet has 26 been sufiiciently driven.

Therefore, an object of the invention is to provide a simple mechanism for automatic control of the rveter for relieving the pressure on the rivet and returning the driving mechanism to a starting position when the rivet has received sufficient pressure.

Another object is to provide mechanism for quicker o eration of the rveter and for eliminating the waste of power. 85 Another object is to provide an adjustable y mechanism for automatic pressure control of the rveter without change of line pressure.

Further objects and certain advantages will appear in the description of the drawings forming a part of this specification, in I which:

.Figura 1 is a general view showing the invention mounted in operative position u on a pneumatic rveter of compression togg e-joint type, certain parts of the control mechanism and rveter being broken away to show the inner construction.

v Figure 2 is a detailed sectional view of the kick-off c linder and piston for Operating the contro ling valve oftheair motor.

Figure 3 is a detailed sectional view taken on line 3-3, Figure 1, showing the forked lever on the kick-off cylinder piston rod for Operating the control rod.

The improvement is shown as applied to a commercial pneumatic compression rveter of the toggle type wli'ich heretofore has been entirely under manual or non-automatic control limiting its capacity as' to size of rivet Or thickness of plates upon which the machine can beV efficiently operated, the piston of the motor Operating the rveter takin a full power or forward stroke for eac rivet drive. A full pressure under a (letermined air line pressure is thus always applied upon the rivet and plates which would be excessive in driving rivets smaller in size to the damage of the metal of either rivet or plates.

Referring' to the drawing, 1 indicates the yoke frame of a rveter, to provide a throat into which the plates to be riveted are inserted between lower and upper dies. The lowerV die 2 is stationary and the upper die 3 is mounted upon a plunger 3a. The plunger 3a is reciprocated by a toggle 4 actuated by a main lever '5 and guide link 5a. The main lever 5 pivotally connects with a piston rod 6 connectlng with a piston 7 in the motor cylinder'vv 8. The driving cylinder 8 has a control Valve casing Or chest 9 mounted thereon, into which the air under pressure is delivered from the supply line 9a. Leading from the valve casing 9 are two passa es 10, 11, entering into the driving cylin er and alternating as supply and exhaust passa es for forward and retreat strokes of the driving piston. vAnother passage 12 leads from the valve casing to the atmosphere and servles as an exhaust passage for the passages 10, 1.

A slide valve 13 is mounted within the casing and is grooved for alternately connecting the passages 10,11 to the exhaust passage 12 and the air supplyline 9a. A shaft 14 extends through the valve casing vfor o erating the valve 11 and a lever 15 is attac ed 'to -the squared end of the shaft. A vrod 16 connects this lever 15 to the control lever 17 pivot'ed to the frame of the rveter as at 18, this control lever being manually operable for controlling the air supply into the driving cylinder. 'The lever 17 is moved manually to Shift the control valve for admitting .a return stroke.

the air into the rear end of the cylinder against the piston for a ,forward or power stroke, and under the prevailing practice the lever is again manually operated for reversing the valve to admit the air pressure against the forward side lof the piston for Under such manual method of control a full pressure against the rivet is developed for the full line pressure multilied by the ratio of the toggle joint, and a ull cylinder of air at thev line pressure is used at each operation, or at least as much of the ,cylinder capacity asis developed by the travel of the piston, and it would require delicate manipulation of the hand lever to obtain aregulated control 0to meet the requirements of variety of sizes of rivets or plate thickness.l The pressure in the driving cylinder must be released and the piston returned to its rear positi'ons, whenever the roper, pressure has been *applied by the riving cylinder necessary to drive the particular size and kind of rivet.

With the present improveinent the control for a reverse stroke of the piston is automatic and at a period when a determined pressure in the cylinder is reached or necessary to drive a particular size and kind of rivet, `without regard to the line pressure on which the machine is operated. The aparatus can be so regulated, that when drivmg rivets smaller in size than the full capacity of the machine, only. suflicient pressure -is exerted to properly drive the rivet, at such point the pressure in the driving cylinder bein'g released and the piston returned to its rear position. Only suflicient air is used to do the Work, and no damage will be done to the rivets or plates in which the rivets are driven. This allows the use of the riveter for a large range of size of rivets and without varying the line pressure, and to .obtain a very uniform work for each of the different size of rivets.

For the automatic control, an unloading or relief valve 20 connects with the rear end of the cylinder by al pipe 19. The pipe 19 includes a hand operated pressure controlling or'reducing valve 35 and pressure gauge 21, the pressure gauge 21 providing .a reading for setting the relief valve., The relief valve 20 controls the admission of air or pressure from the main power cylinder to a cylinder of a valve Operating motor 22 mounted upon the riveter frame for Operating a piston in connection With the valve actuating rod 16 manually actuated by the lever 17.

The unloading or relief valve comprises a casing 23 housing a valve`- 24 acting against a sprin 25, the tension of the spring being adjustaba by means of a screw 26 in the casing for varying the pressure at which the valve opens. Normally the valve 24. is held closed against its seat 27 preventing the flow of air from the driving cylinder to the cylinder 29. When the valve is unseated,

at a predetermined pressure it engages an 31. The piston rod extends through the cylinder head and is provided With a forked lever 33, the forked end of the lever being held between two adjustable collars 34 on the control rod 14.

A choke valve 35 and a valve 36 are placed in the air line 17 between thepressure gauge.

and the driving cylinder. When the unloading valve is set to operate at a low pressure for light work it has been found that as the air is released into the cylinder for the driving operation a sudden rush of highv pressure air through the air line 17 will operate the unloading Valve prematurely and this is prevented by including a choke valve in the conduit or pipe 19 to slow down the flow of air.

The relief valve is preliminarily set by adjusting the tension of .the spring, to apply a determined pressure upon the valve 24:`

necessary for holding the 'valve closed until a determined pressure is reached iii the main power cylinder 8, a degree of pressure the rivet should receive to be properly driven.

The control lever 17 is then pulled ,down-v wardly, this action moving the control rod' 16 upwardly for shifting the valve 18 on the driving cylinder. The same operation throws the piston of the motor 22 upwardly and into position for automatic operation.v

The valve 13 .permits vthe air to flow from the supply line' 9Et into the rear end of the opposite end of the driving cylinder through the groove in the valve which established communication between the port or passa'ge 11 and the exhaust port 12. As the piston 7 is moved forward in its driving stroke, the'air flows'through the line 19 and as the desired pressure is developed in the driving cylinder and exerted on the rivet, the unloading valve is operated by admitting the pressure to the cylinder 29 movin 'the piston 30 for tri pin the valve 13 an effecting a return stro e o the piston 7.

The air in the cylinder 29 escapes through an aperture 37 in the unloading valve casing after the unloa'ding valve spring 25 returns the valve to its normal seat.

The lever 33 has the forked end engaging the control rod to allow for the sli ht swing of the control rod inasmuch as it is pivoted at both ends and is disaligned by translation.

driving cylinder 'and exhausts the air in the 3 be varied as long as the various elements are inder'in said eed line, and a piston in said arranged in their roper order. control cylinder connected to said control Having describe my invention, I claim: lever for Operating said controllever when In combination With a riveting mechathe pressure in 'the driving cylinder unloads 5 nism, a driving cylinder, a driving piston through the unloading valve into thefontrol 15 'therein for Operating the riveting mechacylinder. nism, a control valve for said driving v`cyl- In witness whereofi I hereunto Subscribe inder, a control lever for said valve, a control myname. w feed line leading from said air cylinder, a 10 pressure unloading valve and a control, cyl- RAYMOND'S. OSBORNE. 

